Japanese Patent Application Publication No. 2001-339064 discloses a MOSFET. This MOSFET includes a semiconductor substrate, and an insulated gate electrode located within a trench defined on the semiconductor substrate. The semiconductor substrate includes an n-plus type drain region, an n-minus type drift region located on the drain region, a p-minus type body region located on the drift region, an n-plus type source region located on the body region, the source region appearing on a surface of the semiconductor substrate, and a p-plus type contact region located on the body region, the contact region appearing an the surface of the semiconductor substrate. The trench extends from the surface of the semiconductor substrate to the drift region through the body region. The source region appears on the inner surface of the trench and faces the gate electrode via a gate insulating film. A part of the contact region is located under the source region.